This thing. New head so been sitting. Back together and fuel pressure now all draining back to tank... goes up to 80+ then immediately drops back to 25lbs. I just replaced the check valves and have the accumulator clamped off. I have good space between the FD plunger and arm, what are the possible issues here? I guess I could have FD issues tho it's a calibrated and rebuilt unit (not cheapo), and it's conceivable that one of the new ebay check valves is bad outa box... anything else that could cause this problem? Any way to manually check these valves to rule them out? Really flustered here... thanks for any ideas (89 M103 wagon).